diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/XmlParser.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/XmlParser.java
index 3391f9bec..e2a7c641a 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/XmlParser.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/XmlParser.java
@@ -188,7 +188,7 @@ public class XmlParser extends ParserBase {
     String name = element.getLocalName();
     String path = "/"+pathPrefix(ns)+name;
     
-    StructureDefinition sd = getDefinition(line(element), col(element), ns, name);
+    StructureDefinition sd = getDefinition(line(element), col(element), (ns == null ? "default" : ns), name);
     if (sd == null)
       return null;
 
@@ -240,7 +240,11 @@ public class XmlParser extends ParserBase {
       if (empty(element) && FormatUtilities.FHIR_NS.equals(element.getNamespaceURI())) // this rule only applies to FHIR Content
         logError(line(element), col(element), path, IssueType.INVALID, context.formatMessage(I18nConstants.ELEMENT_MUST_HAVE_SOME_CONTENT), IssueSeverity.ERROR);
       String ns = prop.getXmlNamespace();
-      if (!element.getNamespaceURI().equals(ns))
+      String elementNs = element.getNamespaceURI();
+      if (elementNs == null) {
+        elementNs = "default";
+      }
+      if (!elementNs.equals(ns))
         logError(line(element), col(element), path, IssueType.INVALID, context.formatMessage(I18nConstants.WRONG_NAMESPACE__EXPECTED_, ns), IssueSeverity.ERROR);
     }
   }
@@ -539,7 +543,10 @@ public class XmlParser extends ParserBase {
     xml.setSortAttributes(false);
     xml.setPretty(style == OutputStyle.PRETTY);
     xml.start();
-    xml.setDefaultNamespace(e.getProperty().getXmlNamespace());
+    String ns = e.getProperty().getXmlNamespace();
+    if (ns!=null && !"default".equals(ns)) {
+      xml.setDefaultNamespace(ns);
+    }
     if (hasTypeAttr(e))
       xml.namespace("http://www.w3.org/2001/XMLSchema-instance", "xsi");
     addNamespaces(xml, e);
@@ -549,7 +556,7 @@ public class XmlParser extends ParserBase {
 
   private void addNamespaces(IXMLWriter xml, Element e) throws IOException {
     String ns = e.getProperty().getXmlNamespace();
-    if (ns!=null && !xml.getDefaultNamespace().equals(ns)){
+    if (ns!=null && xml.getDefaultNamespace()!=null && !xml.getDefaultNamespace().equals(ns)){
       if (!xml.namespaceDefined(ns)) {
         String prefix = pathPrefix(ns);
         if (prefix.endsWith(":")) {
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/xml/XMLWriter.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/xml/XMLWriter.java
index 107638ef5..fd4fec5bc 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/xml/XMLWriter.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/xml/XMLWriter.java
@@ -450,7 +450,7 @@ public class XMLWriter extends OutputStreamWriter implements IXMLWriter {
 		if ("http://www.w3.org/XML/1998/namespace".equals(namespace))
 			return "xml:";
 		
-		if (namespace == null || "".equals(namespace))
+		if (namespace == null || "".equals(namespace) || "default".equals(namespace))
 			return "";
 		
 		XMLNamespace ns = findByNamespace(namespace);
diff --git a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTestSuite.java b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTestSuite.java
index ba07c6403..dfd6b8d99 100644
--- a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTestSuite.java
+++ b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTestSuite.java
@@ -212,14 +212,16 @@ public class ValidationTestSuite implements IEvaluationContext, IValidatorResour
     if (content.has("security-checks")) {
       val.setSecurityChecks(content.get("security-checks").getAsBoolean());
     }
-    val.setAssumeValidRestReferences(content.has("assumeValidRestReferences") ? content.get("assumeValidRestReferences").getAsBoolean() : false);
-    System.out.println(String.format("Start Validating (%d to set up)", (System.nanoTime() - setup) / 1000000));
-    if (name.endsWith(".json"))
-      val.validate(null, errors, IOUtils.toInputStream(testCaseContent, Charsets.UTF_8), FhirFormat.JSON);
-    else
-      val.validate(null, errors, IOUtils.toInputStream(testCaseContent, Charsets.UTF_8), FhirFormat.XML);
-    System.out.println(val.reportTimes());
-    checkOutcomes(errors, content, null);
+    if (content.has("logical")==false) {
+      val.setAssumeValidRestReferences(content.has("assumeValidRestReferences") ? content.get("assumeValidRestReferences").getAsBoolean() : false);
+      System.out.println(String.format("Start Validating (%d to set up)", (System.nanoTime() - setup) / 1000000));
+      if (name.endsWith(".json"))
+        val.validate(null, errors, IOUtils.toInputStream(testCaseContent, Charsets.UTF_8), FhirFormat.JSON);
+      else
+        val.validate(null, errors, IOUtils.toInputStream(testCaseContent, Charsets.UTF_8), FhirFormat.XML);
+      System.out.println(val.reportTimes());
+      checkOutcomes(errors, content, null);
+    }
     if (content.has("profile")) {
       System.out.print("** Profile: ");
       JsonObject profile = content.getAsJsonObject("profile");